Cancer is a term used to describe a wide variety of diseases that are each characterized by the uncontrolled growth of a particular type of cell. It begins in a tissue containing such a cell and, if the cancer has not spread to any additional tissues at the time of diagnosis, may be treated by, for example, surgery, radiation, or another type of localized therapy. However, when there is evidence that cancer has metastasized from its tissue of origin, different approaches to treatment are typically used. Indeed, because it is not possible to determine the extent of metastasis, systemic approaches to therapy are usually undertaken when any evidence of spread is detected. These approaches involve the administration of chemotherapeutic drugs that interfere with the growth of rapidly dividing cells, such as cancer cells.
Halichondrin B is a structurally complex, macrocyclic compound that was originally isolated from the marine sponge Halichondria okadai, and subsequently was found in Axinella sp., Phakellia carteri, and Lissodendoryx sp. A total synthesis of halichondrin B was published in 1992 (Aicher et al., J. Am. Chem. Soc. 114:3162-3164, 1992). Halichondrin B has been shown to inhibit tubulin polymerization, microtubule assembly, beta-tubulin crosslinking, GTP and vinblastine binding to tubulin, and tubulin-dependent GTP hydrolysis in vitro. This molecule has also been shown to have anti-cancer properties in vitro and in vivo. Halichondrin B analogs having anti-cancer activities are described in U.S. Pat. No. 6,214,865 B1.
In particular, eribulin mesylate, a Halichondrin B analog, has been developed as an anticancer drug. Recently, eribulin mesylate was approved for the treatment of patients with metastatic breast cancer who have previously received at least two chemotherapeutic regimens for the treatment of metastatic disease, wherein prior therapy may have included an anthracycline and/or a taxane in either the adjuvant or metastatic setting. The ability to predict in advance of treatment whether a cancer patient is likely to be responsive to an anti-cancer agent can guide selection of appropriate treatment, and is beneficial to patients. Accordingly, there is a need for methods for and compositions useful in, assessing or predicting responsiveness to eribulin in patients having cancer and, in particular, breast cancer.